Land Surface Deformation Monitoring of the SongYuan Langya Dam Using MT-InSAR

Conventional settlement monitoring methods are challenged to meet the demands of land deformation monitoring in complex landscapes. This is due to the small working coverage and low efficiency of leveling models or GPS. Synthetic Aperture Radar Interferometry (InSAR) has the unique advantage of combining telemetry, all-weather operation and large coverage, and is widely used in surface deformation monitoring. We studied the Langya Dam in Qian'an County, Jilin, China, using 21 Sentinel-1B images (C-band) acquired during September 2017 - May 2018. The temporal and spatial evolution of Langya Dam was measured using QPS-InSAR, and the variation characteristics of deformation was analyzed. The results show that the Langya dam trended upward during the monitoring period with an average deformation rate of 6.9 cm/a. The maximum cumulative deformation was 12.8 cm, and the deformation in the west was greater than that in the east. Accounting for the topography and the temperature changes at the Langya dam during the monitoring period, groundwater recharge and land surface frost heaving are the dominant factors in land deformation.